Water molecules that are free within the liquid have
attractive forces in all directions. When the water molecule comes in contact
with air, the attractive forces go sideways to surrounding water molecules
causing a “skin” of molecules that are closer together. The paper clip “floats”
because: 1) Molecules are attracted to each other creating a force in a line
that causes resistance to the sinking force of the clip. 2) The paper clip also
sinks a little displacing weight and increasing the surface area of the water
under the paper clip thus increasing the total force holding it up.